John Oliver is probably the best investigative journalist in America today, despite being neither American nor officially a journalist; last week he took on the subject of credit rating agencies, a classic example of his mantra “If you want to do something evil, put it inside something boring.” (note that it’s on HBO, so there is foul language):

As ever, his analysis of the subject is quite good—it’s absurd how much power these agencies have over our lives, and how little accountability they have for even assuring accuracy.

But I couldn’t help but feel that he was kind of missing the point. The credit rating agencies to really be worried about aren’t Equifax, Experian, and Transunion, the ones that assess credit ratings on individuals. They are Standard & Poor’s, Moody’s, and Fitch (which would have been even easier to skewer the way John Oliver did—perhaps we can get them confused with Standardly Poor, Moody, and Filch), the agencies which assess credit ratings on institutions.

These credit rating agencies have almost unimaginable power over our society. They are responsible for rating the risk of corporate bonds, certificates of deposit, stocks, derivatives such as mortgage-backed securities and collateralized debt obligations, and even municipal and government bonds.

S&P, Moody’s, and Fitch don’t just rate the creditworthiness of Goldman Sachs and J.P. Morgan Chase; they rate the creditworthiness of Detroit and Greece. (Indeed, they played an important role in the debt crisis of Greece, which I’ll talk about more in a later post.)

But in fact this underestimates the corruption, because the worst conflicts of interest aren’t even illegal, or weren’t until Dodd-Frank was passed in 2010. The basic structure of this credit rating system is fundamentally broken; the agencies are private, for-profit corporations, and they get their revenue entirely from the banks that pay them to assess their risk. If they rate a bank’s asset as too risky, the bank stops paying them, and instead goes to another agency that will offer a higher rating—and simply the threat of doing so keeps them in line. As a result their ratings are basically uncorrelated with real risk—they failed to predict the collapse of Lehman Brothers or the failure of mortgage-backed CDOs, and they didn’t “predict” the European debt crisis so much as cause it by their panic.

Then of course there’s the fact that they are obviously an oligopoly, and furthermore one that is explicitly protected under US law. But then it dawns upon you: Wait… US law? US law decides the structure of credit rating agencies that set the bond rates of entire nations? Yes, that’s right. You’d think that such ratings would be set by the World Bank or something, but they’re not; in fact here’s a paper published by the World Bank in 2004 about how rather than reform our credit rating system, we should instead tell poor countries to reform themselves so they can better impress the private credit rating agencies.

In fact the whole concept of “sovereign debt risk” is fundamentally defective; a country that borrows in its own currency should never have to default on debt under any circumstances. National debt is almost nothing like personal or corporate debt. Their fears should be inflation and unemployment—their monetary policy should be set to minimize the harm of these two basic macroeconomic problems, understanding that policies which mitigate one may enflame the other. There is such a thing as bad fiscal policy, but it has nothing to do with “running out of money to pay your debt” unless you are forced to borrow in a currency you can’t control (as Greece is, because they are on the Euro—their debt is less like the US national debt and more like the debt of Puerto Rico, which is suffering an ongoing debt crisis you may not have heard about). If you borrow in your own currency, you should be worried about excessive borrowing creating inflation and devaluing your currency—but not about suddenly being unable to repay your creditors. The whole concept of giving a sovereign nation a credit rating makes no sense. You will be repaid on time and in full, in nominal terms; if inflation or currency exchange has devalued the currency you are repaid in, that’s sort of like a partial default, but it’s a fundamentally different kind of “default” than simply not paying back the money—and credit ratings have no way of capturing that difference.

In particular, it makes no sense for interest rates on government bonds to go up when a country is suffering some kind of macroeconomic problem.

The basic argument for why interest rates go up when risk is higher is that lenders expect to be paid more by those who do pay to compensate for what they lose from those who don’t pay. This is already much more problematic than most economists appreciate; I’ve been meaning to write a paper on how this system creates self-fulfilling prophecies of default and moral hazard from people who pay their debts being forced to subsidize those who don’t. But it at least makes some sense.

By letting credit rating agencies decide the rates at which governments must borrow, we are effectively treating national governments as a special case of corporations. But corporations, by design, act for profit and can go bankrupt. National governments are supposed to act for the public good and persist indefinitely. We can’t simply let Greece fail as we might let a bank fail (and of course we’ve seen that there are serious downsides even to that). We have to restructure the sovereign debt system so that it benefits the development of nations rather than detracting from it. The first step is removing the power of private for-profit corporations in the US to decide the “creditworthiness” of entire countries. If we need to assess such risks at all, they should be done by international institutions like the UN or the World Bank.